Computer-aided design (CAD) software allows a user to construct and manipulate complex three-dimensional (3D) models. A number of different modeling techniques can be used to create a 3D model. These techniques include solid modeling, wire-frame modeling, and surface modeling. Solid modeling techniques provide for topological 3D models, where the 3D model is a collection of interconnected topological entities (e.g., vertices, edges, and faces). The topological entities have corresponding supporting geometrical entities (e.g., points, trimmed curves, and trimmed surfaces). The trimmed surfaces correspond to the topological faces bounded by the edges. Wire-frame modeling techniques, on the other hand, can be used to represent a model as a collection of simple 3D lines, whereas surface modeling can be used to represent a model as a collection of exterior surfaces. CAD systems may combine these and other modeling techniques, such as parametric modeling techniques. Parametric modeling techniques can be used to define various parameters for different features and components of a model, and to define relationships between those features and components based on relationships between the various parameters.
CAD systems may also support two-dimensional (2D) objects that are 2D representations of 3D objects. Two- and three-dimensional objects are useful during different stages of a design process. Three-dimensional representations of a model are commonly used to visualize a model in a physical context because the designer can manipulate the model in 3D space and can visualize the model from any conceivable viewpoint. Two-dimensional representations of a model are commonly used to prepare and formally document the design of a model.
A design engineer is a typical user of a 3D CAD system. The design engineer designs physical and aesthetic aspects of 3D models, and is skilled in 3D modeling techniques. The design engineer creates parts and may assemble the parts into a subassembly. A subassembly may also consist of other subassemblies. An assembly is designed using parts and subassemblies. Parts and subassemblies are hereinafter collectively referred to as components.
In some cases a user may wish to create a broken view of a 2D CAD model. Broken views make it possible to display a drawing view in a larger scale on a smaller size drawing sheet by removing from the view sections of the model that are redundant or in some way deemed unnecessary to the view. The design engineer creates a gap or break in the view using a pair of break lines. Reference dimensions and model dimensions associated with the broken area should reflect the actual model values.
In current state-of-the-art computer-aided-design systems, broken views in a feature-based 3D model may be created by adding features directly to the 3D model. These features do not preserve the 3D model in its unbroken state, so to query and annotate the 3D model, the interruption features must be removed. Moreover, if dimensions are required in the broken state, the values for the dimensions must be overwritten to display the proper value.
For example, to add a break to a 3D model using SolidWorks 2014 software, available from Dassault Systemes SolidWorks Corporation of Waltham, Mass., the user first adds a cut feature to the area to be removed within a 3D solid model, which leaves a large gap in the 3D model, with new separate solid bodies on each side of the gap. In the case of a straight cut, the user has the ability to slice a solid body with a plane. For more complex cuts, the user must first create a cutting tool body by creating a ziz-zag profile or other profile then use a SolidWorks command such as Cut-Extrude to generate the cut. The user then calculates the distance necessary to move each body equidistantly towards each other. Upon user selection of the Move/Copy Bodies command, a move body operation is then applied twice, one for each of the two bodies, thereby moving the two bodies closer together as previously calculated and also further modifying the definition of each of the solid bodies. Once this is complete, the measure tool no longer correctly measures the 3D model and dimensions are no longer correct since the 3D model was directly changed into two separate and distinct solid bodies to achieve the broken model result. Moreover, some state-of-the-art CAD systems are unable to produce accurate axonometric views that include one or more breaks in a 3D model included in a 2D drawing.
Time-saving advantages can be obtained by maintaining and assuring the accuracy and consistency of the data in a broken 3D model and the same 3D model in an unbroken state enabling users to (a) quickly generate broken 3D models according to industry standards and applying the industry standards to views of the 3D models within respective 2D drawings, (b) interact with the broken 3D models, (c) easily modify the broken 3D models, and (d) measure and annotate the broken 3D models.
Often, modifying particular portions of a 3D model when displaying the entire or a large portion of the 3D model makes such modifications cumbersome and inefficient due to the scale at which the 3D model needs to be displayed. To increase productivity, current state-of-the-art CAD systems would benefit from a system and method for providing an abbreviated rendering of a 3D model thereby allowing a user to easily modify particular portions of the 3D model.